Cycles - camera motion blur only on certain objects?
One possiple way to solve this problem is by assigning a object or material index to the objects, that should not be blured. than you enable the Vector pass in your render layer. In the compositor you can than remove your objects from the image (with the id-mask) and replace them with black (do the same with the vector by just handling the vector like an image), apply the vector blur and add your objects again.